shortburb Posted February 4, 2015 Report Posted February 4, 2015 Hey guys sorry for the rookie question. I didn't get far with the search feature Iv had this banshee for a bit and it needs a top end. Pistons measured at 63.4 and bores measured at 63.5. Standard bore is 64.0mm right? I will get another micrometer and check it against mine, other than my mic being off-is a smaller than stock bore thing common? Im afraid to order 64mm pistons and they don't even go into the bores... This is an stock bike less air box lid removal and a pod filter. I haven't even spent time messing with jetting because it runs fair and doesn't foul plugs. Id like to order pistons soon Quote
sheerider11 Posted February 4, 2015 Report Posted February 4, 2015 Are you not gonna bore the cylinders? Why is it apart? Why wouldn't you do a fresh top end? Do you concider a top end just new pistons? Quote
sleeper06 Posted February 4, 2015 Report Posted February 4, 2015 That measurement is fairly common give or take,never just throw Pistons in the should be measured and clearances properly even if it just takes a hone. The machine shop that does all my work has a wiseco sizing book and can give you an answer on piston size with consideration to roundness of bore etc. moral of story never just throw anything in if you want it to live Quote
J-Madd Posted February 5, 2015 Report Posted February 5, 2015 Are the pistons in it now stock? You can put new stockers (with fresh hone) and run it if so. As long as it's not out of round. You can't however put in a stock replacement forged (wiseco) piston within boring it. 1 Quote
shortburb Posted February 5, 2015 Author Report Posted February 5, 2015 Both holes made 70 psi thats why I am doing a top end. Ring end gap is huuuuuuuge. id be content just doing rings and top end bearings but i want to fgure out what pistons are in it. Quote
shortburb Posted February 5, 2015 Author Report Posted February 5, 2015 iv been doing some looking around and these appear to be stock pistons. Im sure you will think Im cheap but can I buy a set of OE rings and head/base gaskets and put it back together? i dont want to spend the money/time on boring the cylinders right now. this thing needs freshened up not a whole crispy top end ya know Quote
shortburb Posted February 5, 2015 Author Report Posted February 5, 2015 well I take that back. Im seeing about $260 for wiseco pistons and boring service...might do that Quote
oldskool Posted February 5, 2015 Report Posted February 5, 2015 You might want to look at Vito's super stock pistons 1 Quote
Larry's Shee Posted February 5, 2015 Report Posted February 5, 2015 You need to acurately measure bore and pistons to determine piston clearance. IF you are more than half the service "limit" might as well do everything right. Even tho new rings may improve the compression for a while, you still have sloppy hoes. Stock pistons don't like sloppy hoes. They get to sloppy, they break, then you will probably need more than new pistons and a bore job. JMHO, your results may, and will vary. 1 Quote
Rigid_Banshee Posted February 9, 2015 Report Posted February 9, 2015 The Pistons in the photo are stock Yamaha puts a fat ugly arrow to point to the exhaust side instead of stamping one like Wiseco does Quote
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